<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>

<body>
  <!-- 
      src    视频资源地址
     controls  视频工具栏
     autoplay  自动播放
     loop 循环播放
     poster 视频封面图片地址
   -->
  <video id="myvideo" src="./source/1.mp4" controls autoplay loop
    poster="https://dss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=1802523258,3502855802&fm=26&gp=0.jpg"></video>
  <button id="play">播放</button>
  <button id="addVideo">增加音量</button>
  <script>
    var playBtn = document.getElementById("play");
    var myVideo = document.getElementById("myvideo")
    playBtn.onclick = function () {
      myVideo.play()
    }
    // 视频声音增加到最大  0-1
    addVideo.onclick = function () {
      // 视频的音量属性 volume
      myVideo.volume = 1;
    }
    //视频的所有属性
    // https://www.w3school.com.cn/tags/html_ref_audio_video_dom.asp
  </script>
</body>

</html>